UHC insurance help?

21f I have a consultation coming up in about two weeks and I'm so anxious thinking about fighting with my insurance. I have UHC (UnitedHealthcare). I have the surgery code and diagnosis code written down and it's covered under preventative. I'm asking for any tips with insurance, or if any of you have UHC, how was it? Did they deny claim? Did they fight back a lot? What certain things did you say for it to go smoother? I'd love any personal stories about calling insurance and getting it handled. Thanks!